X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fnss-myhostname%2Fnss-myhostname.c;h=60e256d54fc0b5c3d5f1ada27d7a8b23ac489bf4;hp=834a80690fdff0338f87701497889606aec8a0a4;hb=cac914e643a50c72893c5478f6886e0978f8fa18;hpb=cbc06dcd8f74e9e757c55884a4acf49784fc3444 diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c index 834a80690..60e256d54 100644 --- a/src/nss-myhostname/nss-myhostname.c +++ b/src/nss-myhostname/nss-myhostname.c @@ -25,13 +25,18 @@ #include #include #include -#include #include #include #include #include #include "ifconf.h" +#include "macro.h" + +/* Ensure that glibc's assert is used. We cannot use assert from macro.h, as + * libnss_myhostname will be linked into arbitrary programs which will, in turn + * attempt to write to the journal via log_dispatch() */ +#include /* We use 127.0.0.2 as IPv4 address. This has the advantage over * 127.0.0.1 that it can be translated back to the local hostname. For @@ -42,8 +47,6 @@ #define LOCALADDRESS_IPV6 &in6addr_loopback #define LOOPBACK_INTERFACE "lo" -#define ALIGN(a) (((a+sizeof(void*)-1)/sizeof(void*))*sizeof(void*)) - enum nss_status _nss_myhostname_gethostbyname4_r( const char *name, struct gaih_addrtuple **pat, @@ -96,33 +99,47 @@ enum nss_status _nss_myhostname_gethostbyname4_r( int32_t *ttlp) { unsigned lo_ifi; - char hn[HOST_NAME_MAX+1]; + char hn[HOST_NAME_MAX+1] = {}; + const char *canonical = NULL; size_t l, idx, ms; char *r_name; struct gaih_addrtuple *r_tuple, *r_tuple_prev = NULL; struct address *addresses = NULL, *a; unsigned n_addresses = 0, n; + uint32_t local_address_ipv4; - memset(hn, 0, sizeof(hn)); - if (gethostname(hn, sizeof(hn)-1) < 0) { - *errnop = errno; - *h_errnop = NO_RECOVERY; - return NSS_STATUS_UNAVAIL; - } + if (strcasecmp(name, "localhost") == 0) { + /* We respond to 'localhost', so that /etc/hosts + * is optional */ - if (strcasecmp(name, hn) != 0) { - *errnop = ENOENT; - *h_errnop = HOST_NOT_FOUND; - return NSS_STATUS_NOTFOUND; - } + canonical = "localhost"; + local_address_ipv4 = htonl(INADDR_LOOPBACK); + } else { + /* We respond to our local host name */ - /* If this fails, n_addresses is 0. Which is fine */ - ifconf_acquire_addresses(&addresses, &n_addresses); + if (gethostname(hn, sizeof(hn)-1) < 0) { + *errnop = errno; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + + if (strcasecmp(name, hn) != 0) { + *errnop = ENOENT; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + /* If this fails, n_addresses is 0. Which is fine */ + ifconf_acquire_addresses(&addresses, &n_addresses); + + canonical = hn; + local_address_ipv4 = LOCALADDRESS_IPV4; + } /* If this call fails we fill in 0 as scope. Which is fine */ - lo_ifi = if_nametoindex(LOOPBACK_INTERFACE); + lo_ifi = n_addresses <= 0 ? if_nametoindex(LOOPBACK_INTERFACE) : 0; - l = strlen(hn); + l = strlen(canonical); ms = ALIGN(l+1)+ALIGN(sizeof(struct gaih_addrtuple))*(n_addresses > 0 ? n_addresses : 2); if (buflen < ms) { *errnop = ENOMEM; @@ -133,7 +150,7 @@ enum nss_status _nss_myhostname_gethostbyname4_r( /* First, fill in hostname */ r_name = buffer; - memcpy(r_name, hn, l+1); + memcpy(r_name, canonical, l+1); idx = ALIGN(l+1); if (n_addresses <= 0) { @@ -153,7 +170,7 @@ enum nss_status _nss_myhostname_gethostbyname4_r( r_tuple->next = r_tuple_prev; r_tuple->name = r_name; r_tuple->family = AF_INET; - *(uint32_t*) r_tuple->addr = LOCALADDRESS_IPV4; + *(uint32_t*) r_tuple->addr = local_address_ipv4; r_tuple->scopeid = (uint32_t) lo_ifi; idx += ALIGN(sizeof(struct gaih_addrtuple)); @@ -176,7 +193,11 @@ enum nss_status _nss_myhostname_gethostbyname4_r( /* Verify the size matches */ assert(idx == ms); - *pat = r_tuple_prev; + /* Nscd expects us to store the first record in **pat. */ + if (*pat) + **pat = *r_tuple_prev; + else + *pat = r_tuple_prev; if (ttlp) *ttlp = 0; @@ -187,31 +208,34 @@ enum nss_status _nss_myhostname_gethostbyname4_r( } static enum nss_status fill_in_hostent( - const char *hn, + const char *canonical, const char *additional, int af, + struct address *addresses, unsigned n_addresses, + uint32_t local_address_ipv4, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int32_t *ttlp, char **canonp) { - size_t l, idx, ms; - char *r_addr, *r_name, *r_aliases, *r_addr_list; + size_t l_canonical, l_additional, idx, ms; + char *r_addr, *r_name, *r_aliases, *r_alias = NULL, *r_addr_list; size_t alen; - struct address *addresses = NULL, *a; - unsigned n_addresses = 0, n, c; + struct address *a; + unsigned n, c; alen = PROTO_ADDRESS_SIZE(af); - ifconf_acquire_addresses(&addresses, &n_addresses); - for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++) if (af == a->family) c++; - l = strlen(hn); - ms = ALIGN(l+1)+ + l_canonical = strlen(canonical); + l_additional = additional ? strlen(additional) : 0; + ms = ALIGN(l_canonical+1)+ + (additional ? ALIGN(l_additional+1) : 0) + sizeof(char*)+ + (additional ? sizeof(char*) : 0) + (c > 0 ? c : 1)*ALIGN(alen)+ (c > 0 ? c+1 : 2)*sizeof(char*); @@ -222,15 +246,27 @@ static enum nss_status fill_in_hostent( return NSS_STATUS_TRYAGAIN; } - /* First, fill in hostname */ + /* First, fill in hostnames */ r_name = buffer; - memcpy(r_name, hn, l+1); - idx = ALIGN(l+1); + memcpy(r_name, canonical, l_canonical+1); + idx = ALIGN(l_canonical+1); + + if (additional) { + r_alias = buffer + idx; + memcpy(r_alias, additional, l_additional+1); + idx += ALIGN(l_additional+1); + } - /* Second, create (empty) aliases array */ + /* Second, create aliases array */ r_aliases = buffer + idx; - *(char**) r_aliases = NULL; - idx += sizeof(char*); + if (additional) { + ((char**) r_aliases)[0] = r_alias; + ((char**) r_aliases)[1] = NULL; + idx += 2*sizeof(char*); + } else { + ((char**) r_aliases)[0] = NULL; + idx += sizeof(char*); + } /* Third, add addresses */ r_addr = buffer + idx; @@ -249,7 +285,7 @@ static enum nss_status fill_in_hostent( idx += c*ALIGN(alen); } else { if (af == AF_INET) - *(uint32_t*) r_addr = LOCALADDRESS_IPV4; + *(uint32_t*) r_addr = local_address_ipv4; else memcpy(r_addr, LOCALADDRESS_IPV6, 16); @@ -308,7 +344,11 @@ enum nss_status _nss_myhostname_gethostbyname3_r( int32_t *ttlp, char **canonp) { - char hn[HOST_NAME_MAX+1]; + char hn[HOST_NAME_MAX+1] = {}; + struct address *addresses = NULL; + unsigned n_addresses = 0; + const char *canonical, *additional = NULL; + uint32_t local_address_ipv4; if (af == AF_UNSPEC) af = AF_INET; @@ -319,20 +359,39 @@ enum nss_status _nss_myhostname_gethostbyname3_r( return NSS_STATUS_UNAVAIL; } - memset(hn, 0, sizeof(hn)); - if (gethostname(hn, sizeof(hn)-1) < 0) { - *errnop = errno; - *h_errnop = NO_RECOVERY; - return NSS_STATUS_UNAVAIL; - } + if (strcasecmp(name, "localhost") == 0) { + canonical = "localhost"; + local_address_ipv4 = htonl(INADDR_LOOPBACK); + } else { + if (gethostname(hn, sizeof(hn)-1) < 0) { + *errnop = errno; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + + if (strcasecmp(name, hn) != 0) { + *errnop = ENOENT; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + ifconf_acquire_addresses(&addresses, &n_addresses); - if (strcasecmp(name, hn) != 0) { - *errnop = ENOENT; - *h_errnop = HOST_NOT_FOUND; - return NSS_STATUS_NOTFOUND; + canonical = hn; + additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL; + local_address_ipv4 = LOCALADDRESS_IPV4; } - return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, canonp); + return fill_in_hostent( + canonical, additional, + af, + addresses, n_addresses, + local_address_ipv4, + host, + buffer, buflen, + errnop, h_errnop, + ttlp, + canonp); } enum nss_status _nss_myhostname_gethostbyname2_r( @@ -376,9 +435,12 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r( int *errnop, int *h_errnop, int32_t *ttlp) { - char hn[HOST_NAME_MAX+1]; - struct address *addresses = NULL, *a; + char hn[HOST_NAME_MAX+1] = {}; + struct address *addresses = NULL; + struct address *a; unsigned n_addresses = 0, n; + uint32_t local_address_ipv4 = LOCALADDRESS_IPV4; + const char *canonical = NULL, *additional = NULL; if (len != PROTO_ADDRESS_SIZE(af)) { *errnop = EINVAL; @@ -391,10 +453,18 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r( if ((*(uint32_t*) addr) == LOCALADDRESS_IPV4) goto found; + if ((*(uint32_t*) addr) == htonl(INADDR_LOOPBACK)) { + canonical = "localhost"; + local_address_ipv4 = htonl(INADDR_LOOPBACK); + goto found; + } + } else if (af == AF_INET6) { - if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) + if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) { + additional = "localhost"; goto found; + } } else { *errnop = EAFNOSUPPORT; @@ -416,20 +486,33 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r( *h_errnop = HOST_NOT_FOUND; free(addresses); + return NSS_STATUS_NOTFOUND; found: - free(addresses); + if (!canonical) { + if (gethostname(hn, sizeof(hn)-1) < 0) { + *errnop = errno; + *h_errnop = NO_RECOVERY; - memset(hn, 0, sizeof(hn)); - if (gethostname(hn, sizeof(hn)-1) < 0) { - *errnop = errno; - *h_errnop = NO_RECOVERY; + free(addresses); - return NSS_STATUS_UNAVAIL; + return NSS_STATUS_UNAVAIL; + } + + canonical = hn; } - return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, NULL); + return fill_in_hostent( + canonical, additional, + af, + addresses, n_addresses, + local_address_ipv4, + host, + buffer, buflen, + errnop, h_errnop, + ttlp, + NULL); }